Kit (ConvertKit) vs Substack: Email Automation Platform vs Newsletter Publishing Network

Kit (ConvertKit) is the better platform if you need email automations, sell digital products, or want full ownership of your subscriber list without a platform taking a cut of your revenue. Kit's Creator plan starts at $25/mo for up to 1,000 subscribers, and its free plan supports up to 10,000 subscribers — making it the higher-investment but more capable tool for building a creator business.

Substack is the stronger choice for writers who want to start publishing immediately at zero cost, benefit from built-in reader discovery, and are comfortable with Substack taking a 10% cut of paid subscription revenue. There is no monthly fee until you start earning, which makes it genuinely risk-free to launch. The trade-off is giving up automation capabilities and accepting the platform's network constraints.

The decision comes down to one question: do you want a marketing platform that gives you full control, or a publishing network that lowers the barrier to launch? Both paths lead to a functioning newsletter — they just charge you differently and give you different tools for growing it.

Kit (formerly ConvertKit, rebranded in 2024) is a creator-focused email marketing platform built around list ownership, visual automations, and digital product sales. It was created for professional bloggers and content creators who needed more than a broadcast tool — specifically, the ability to build automated email funnels that respond to subscriber behavior and drive product purchases. Kit Commerce allows creators to sell digital downloads, courses, and subscriptions directly through the platform.

Substack is a newsletter publishing network that combines email delivery with a web publication and a built-in reader marketplace. Writers can publish for free and charge subscribers a recurring fee with no upfront cost — Substack earns its revenue by taking 10% of all paid subscription income. Beyond email, Substack has invested heavily in social features including Notes (its Twitter-like feed), Recommendations, and in-app discovery that helps new writers find audiences through the platform's existing readership.

The fundamental difference between Kit and Substack is their business model, which shapes every product decision. Substack is a publishing network — it has financial incentives to help you grow your subscriber count and convert them to paid because it takes 10% of that revenue. Kit is a marketing platform — it charges you a flat fee and gives you automation tools to build your own funnels, keep 100% of your revenue, and integrate with any commerce system you choose.

On economics, Substack looks cheaper at launch (zero monthly cost) but becomes expensive once paid subscription revenue grows. At $1,000/mo in subscription revenue, Substack takes $100. At $5,000/mo, it takes $500 — more than Kit's monthly cost at most list sizes. Kit's Creator plan pricing scales with list size but does not take a cut of any revenue you generate. Creators who expect meaningful subscription income typically find Kit's economics more favorable once they model both costs.

Choose Kit when you need control and capabilities beyond publishing. If you sell digital products, run automated email funnels, or want to segment subscribers by behavior and purchase history, Kit gives you the tools to build that infrastructure. Kit is also the right choice if subscription revenue is central to your model and you want to stop paying a platform percentage once you are generating meaningful income.

Choose Substack when you want to start publishing immediately with no upfront cost and benefit from a built-in reader network. Substack's discovery features — Recommendations, Notes, and the app feed — provide organic growth pathways that Kit cannot match because Kit has no reader network. If you are a writer who wants to focus on content rather than funnel architecture, Substack's simplicity is a genuine advantage.

Kit's free plan covers up to 10,000 subscribers with unlimited email sends but no automations or third-party integrations. The Creator plan starts at $25/mo for up to 1,000 subscribers, adding visual automations, integrations, and free migration. Creator Pro starts at $50/mo for 1,000 subscribers and includes subscriber scoring and advanced reporting. Pricing scales with list size — a 10,000-subscriber Creator account costs $119/mo. Kit takes zero revenue cut on any product sales or paid subscriptions.

Substack charges no monthly fee. Writers publish free until they choose to enable paid subscriptions, at which point Substack takes 10% of gross subscription revenue. Stripe payment processing adds another 2.9% plus $0.30 per transaction. There are no tiers — all features, including Recommendations and the Substack app, are available at zero cost. For creators just starting out, this is the most accessible entry point in newsletter publishing.

Substack setup takes minutes — you register, configure your publication, and can publish your first post within an hour. There is no domain configuration required by default (your publication lives on a Substack subdomain), and paid subscriptions can be enabled with a single toggle once your Stripe account is connected. Migrating away from Substack later requires exporting your subscriber list as a CSV — you own the list, but you lose the network relationships and in-app subscribers.

Kit's onboarding is more involved but well-documented. You will set up your first opt-in form, configure welcome email automations, and integrate with any external tools. Kit offers free migration assistance on paid plans, which is valuable when moving from a platform with complex existing automation logic. Day-to-day, Substack's interface is centered on the editor and your posts; Kit's interface is centered on your subscriber list, tags, and automations.

Creators building a subscription business with plans to sell additional products — courses, ebooks, group coaching — should choose Kit. The automation capabilities, Kit Commerce, and zero revenue share create a more sustainable economics model once you are generating real subscription income. Kit's 10,000-subscriber free plan also makes it easy to start with no cost and upgrade only when you need automations.

Writers who want to start a paid newsletter as simply as possible, with the best chance of organic discovery through an existing reader network, should start on Substack. The zero-cost model means you can validate whether people will pay for your content before investing in a monthly platform subscription. Creators who outgrow Substack's limitations — primarily the revenue cut and lack of automations — frequently migrate to Kit or Beehiiv once their subscription revenue justifies it.